I am responding b/c I have just finished test playing both models for about four weeks (I tested an ex and a z lacquered and unlacquered). I chose the ex, but I loved all three horns. In all, the action, focus, intonation, and quickness of response of the ex was slightly superior to the z's for me. Grant you that these are all relative. There is a big difference b/t the z lacquered and unlacquered, and I liked the latter more due to the great resonance. They both have great sounds. I emailed and telephoned a few Yamaha representatives and gained the following (though you simply have to read available literature to capture the following). The ex bell is a hand hammered one piece while the z is a hydroformed two piece. The z's are a french brass version of the 62ii (and I mean identical), but with a different color neck receiver, custom neck, bigger strap ring, and custom engraving. The ex is the 875, but with Yamaha's listed improvements. The z has the bore, bow, and bell size of the 62ii. Yamaha simply inputs a different brass into the the 62ii processing, tweaks a few things at the end, and, well . . . a great horn. Hope this helps.